Electronic devices, such as those containing semiconductors, typically generate a significant amount of heat during operation. To cool the semiconductors, a thermally conductive composition is used to provide an intimate contact between the semiconductor and a cold sink to facilitate the heat transfer out of the semiconductor and to the cold sink. Thermally conductive compositions are used to improve the heat flux between hot devices/substrates and cold sinks/spreaders. Thermally conductive compositions may consist of thermally conductive fillers and a resin binder. As the concentration of thermally conductive fillers increase, the thermal conductivity of the system improves. However, increasing filler loading can sacrifice performance characteristics (e.g. adhesion, flexibility) or application requirements (e.g. paste viscosity, handling characteristics of film compositions).
Thermally conductive compositions with a low viscosity and good flowability are desirable for the more powerful and denser semiconductor chips currently being designed. Low viscosity thermally conductive compositions are desirable for fragile chips and for the solder bonds that attach the chips to a substrate, because of the minimal force necessary to apply the composition to the semiconductor chip and the resulting decrease in the risk of compromising the integrity of the chip.
There continues to be a need in the art for a thermally conductive composition with good thermal conductivity and good flowability. The present invention addresses this need.